AutomationDirect DL105, User Manual

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Appendix
G
Numbering
S
ystems
G--10
Numbering Systems
DL105 PLC User Manual, 3rd Edition
AutomationDirect.com Products and Data Types
The Direct LOGIC PLC family uses the octal numbering system for all addressing
which includes: inputs, outputs, internal V--memory locations, timers, counters,
internal control relays (bits), etc. Most data in the PLC, including timer and counter
current values, is in BCD format by default. User data in V--memory locations may be
stored in other data types if it is changed by the programmer, or comes from some
external source, such as an operator interface. Any manipulation of data must use
instructions appropriate for that data type which includes: Load instructions, Math
instructions, Out box instructions, comparison instructions, etc. In many cases, the
data can be changed from one data type to another, but be aware of the limitations of
the various data types when doing so. For example, to change a value from BCD to
decimal (binary), use a BIN instruction box. To change from BCD to a real number,
use a BIN and a BTOR instruction box. When using Math instructions, the data
types must match . For example, a BCD or decimal (binary) number cannot be
added to a real number, and a BCD number cannot be added to a decimal (binary)
number. If the data types are mismatched, the results of any math operation will be
meaningless.
When using the Data View in
Direct SOFT, be certain that the proper format is
selected for the element to be viewed. The data type and length is selected using the
drop--down boxes at the top of the Data View window. Also notice that BCD is called
BCD/Hex. Remember that BCD is a subset of hexadecimal so they share a display
format even though the values may be different. This is where good documentation
of the data type stored in memory is crucial.
In the C--more and C--more Micro--Graphic HMI operator panels, the 16--bit BCD
format is listed as “BCD int 16“. Binary format is either “Unsigned int 16“ or “Signed
int 16“ depending on whether or not the value can be negative. Real number format
is “Floating PT 32”.
More available formats are, “BCD int 32“, “Unsigned int 32“ and “Signed int 32“.
Direct LOGIC PLCs
C--more/C--more
Micro--Graphic
Panels